1. Field of the Invention
This invention relates to a process for producing compact silicon nitride ceramics.
2. Description of the Prior Art
Silicon nitride (Si.sub.3 N.sub.4) ceramics have a unique low degree of thermal expansion, high mechanical strength and superior thermal stability, and therefore, have attracted attention as various thermally stable materials of high strength. However, ceramic products thereof have unsatisfactory sinterability, and various efforts have been made to improve this property. Products which have emerged from these efforts are still unsatisfactory; particularly, bubbling occurs during manufacture at high temperature in air, which is an inherent defect of silicon nitride ceramics. Therefore, elimination of this defect has been strongly desired.